Carbon materials have low specific gravity and excellent heat resistance, corrosion resistance, slidability, electric conductivity, heat conductivity, and workability, and are therefore conventionally used in a wide variety of fields including semiconductor technology, metallurgy, mechanical technology, electrotechnology, and nuclear technology.
However, carbon materials generally have a problem in that they are poor in oxidation resistance and strength. To solve this problem, it has been considered to combine a carbon material with another material, such as ceramics, to produce a complex.
Patent Literatures 1 to 3 disclose methods for improving the oxidation resistance of a carbon-based material by forming a silicon carbide coating on the surface of the carbon-based material.
Examples of processes of forming a silicon carbide coating which are used in the above disclosures include a chemical vapor deposition process (hereinafter, referred to as a CVD process) for depositing silicon carbide generated by vapor phase reaction and a conversion process (hereinafter, referred to as a CVR process) for forming silicon carbide by reacting carbon with a silicon component using carbon in a base material as a reaction source.
Furthermore, there is proposed, as a complex material composed of silicon carbide and a carbon material, a sintered silicon carbide/carbon complex in which silicon carbide fine powder and graphite particles are mixed and the mixture is sintered with high density by spark plasma sintering (see Patent Literature 4).
A conceivable alternative process for producing such a sintered silicon carbide/carbon complex is the process of sintering graphite particles each coated with a silicon carbide coating.
Patent Literature 5 proposes to coat the surfaces of carbon nanotubes with silicon carbide through a CVD process or a CVR process. Patent Literature 6 proposes to coat the surface of diamond with a silicon carbide coating through a CVD process or a CVR process.
However, upon coating of the surface of a carbon base material, such as graphite, with a silicon carbide coating through the CVD process or the CVR process, there arises a problem in that the surface cannot be uniformly coated.